Dental engine



(No Model.) 2 Sheets-Sheet 1.

J. HOOD & S. H. REYNOLDS.

DENTAL ENGINE.

No. 388,200. Patented Aug. 21, 1888.

N FUCHS Phow-Lnho npher. Wishlngton. Dv c.

2 Sheets-Sheet 2.

(No Model.)

J. HOOD 8v S. H. REYNOLDS.

DENTAL ENGINE.

Patented Aug. 21, 1888.

8141mm FOE, Wfipivd.

UNITED STATES PATENT OFFICE.

JOHN HOOD AND STEPHEN H. REYNOLDS, OF BOSTON, MASSACHUSETTS.

DENTAL ENGINE.

SPECIFICATION forming part of Letters Patent No. 388,200, dated August21, 1888.

Application filed January 12, 1888.

To all whom it may concern:

Be it known that we, JOHN HOOD and STEPHEN H. Rurxonns, citizens of theUnited States, residing at Boston, in the county of Suffolk and State ofMassachusetts, have invented certaiu new and useful Improvements inDental Engines; and we do declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and to the letters and figuresof reference marked thereon, which form a part of this specification.

This invention relates to the construction of dental engines; and itconsists in certain improvements on the engine for which a patent, No.381,783, was granted to me on the 24th day of April, 1888.

These improvements relate especially to the construction and arrangementof the spring by which the extensionbar is supported to the upwardextension of the arms of the standard above the fly-wheel to receive ahandle by which the machine may be lifted and carried when it is desiredto change its position, to the peculiar construction of the universaljoint in the arm which carries the operatingtool, and to the adjustablebrace for supporting said arm, all as will be hereinafter fullydescribed, and illustrated in the drawings forming a part of thisspecification, in which drawings- Figure 1 is a perspective view of theengine complete. Fig. 2 is an enlarged side elevation showing the methodof applying thespring which supports the extensionbar. Fig. 3 shows thebifurcated portion of the standard with the spring attachments.elevation, partly in section, of the upper end of the extensioirbar andtool-carrying arm folded and resting upon its supporting-hook as whennot in use. Fig. 5 is a cross-section of the arm on the line :20 .r,with the universal joint in different positions. Fig. 6 is a planshowing the arm extended, the outer part be yond thejoint being shown bydotted lines in different positions. Fig. 7 is a side elevation of theupper part of the extension-bar with the supportinghook and braceattachment. Fig. 8 is a perspective View of the spring employed tosupport the extension-bar. Fig. 9

Fig. 4 is aside Serial No. 200,480. (No model.)

is an enlarged section of the globular universal joint, showing themanner of connecting its two halves.

In the different views of the machine, A represents the base, and I thestandard, which parts may be made adjustable one upon the other orsecured together in a fixed position. The base carries the treadle A, bywhich motion is communicated to the moving parts of the machine. Thestandard is bifurcated, its two arms a (1 extending upward above theflywheel O, and are provided at their upper ends over said ily-wheelwith the connecting cross-piece or handle a, by which the machine may bereadily lifted when it is desired to change its position.

Journaled in the arms a a is the crankshaft (J, connected with thetreadle A by a suitable pitman, B, through which motion is transmittedfrom said treadlc to the fly-wheel.

The extension-bar D is forked at its lower end, forming the arms 1) D,extending at right angles to the body of the bar and embracing thefly-wheel. The ends of these arms I) are journaled upon the crank-shaft,so that the extension-bar may be moved or swung in the plane of thefiy-wheels rotation.

In order to support this bar ordinarily in a vertical or nearly verticalposition,we employ the spring E, formed, as shown in Fig. 8 of thedrawings, of a piece of steel or other wire having suitable resilientproperties and secured at its middle in the clamp E, which is in turnsecured by a screw or bolt, b, to the end of the extension-bar. The twoends of the spring are bent to a right angle at each side of the clamp,extend parallel with each other beneath the arms 1), and have theirextremities passed through suitable slots or openings, c c, in the armsa a of the standard I and in which they may be secured at any desiredpoint by set-screws I), thus enabling the operator to change the normalposition of the extension-bar as well as swing it back and forth to acertain extent when the machine is in use or at rest. This extension-barD is tubular and receives in its upper end the stem F ofthe bracket F,between the upwardly-projecting ears of which is pivoted one end of thetubular casing G, which, with the casing G, forms the sheath withinwhich the rotating shaft II, giving motion to the implementused,

is incased. Motion is imparted to this shaft by a band running in agroove in the periphery of the fly-wheel and over the grooved pnlley K,secured upon the end of said shalt between the ears of the bracket F.

The two parts G and G of the tubular shaftcase are each provided withone of the hemispherical cups I or 1, the part G being connected to thecup I by means of the sleeve d, which is allowed to turn on the ends ofsaid case G through at least two thirds of a circle, as illustrated inFig. 5, which shows a section of the sleeve and case at theirjunction,the sleeve being prevented from making a complete revolution on the caseG by the key v, at tached to and projecting from said case, which keycomes in contact with a projection, n, of the sleeve d. The cup I isconnected with the casing G by a sleeve, (1, secured to said cas ing bya set-screw or other suitable means, but without motion thereon. Thesetwo hemispherical cups I and I are secured together by forming anoutwardlyextending flange, 0, upon the part I and upon the cup I asimilar outwardly extending flange, c, of greater width,which extendsbeyond the outer edge of flange c and returns over it, thus forming arecess entirely surrounding the cups,within which the flange 0 is freeto turn.

In order to allow the two cups to be taken apart for repairs or otherpurposes, a part ot' the flange c, as f, is made removable, beingsecured in place by screws or other suitable devices. lVhen this partfisremoved,the flange on the cup I may be drawn out of the recess in theflange of the cup 1, thus disconnecting the two parts G and G of theshaftcase and allowing access to the interior. The shaft II terminatesinthe sleeve (1, where it is connected to the flexible shaft or wire coilJ, the opposite end of which coil is secured to the end of the shaft Hin the sleeved. This shaft ll passes through the tubular case G and isconnected with the coil and shaft in the handpiece L in the usualmanner. It will be seen that this arrangement of the shafts, theircasings, and their globular connection makes a complete universal joint,allowing the arm to be doubled back and the hand piece suspended fromthe hook g, attached to one side of the bracket F, as shown in Fig. 4 ofthe drawings, or to be moved in any direction necessary during themanipulation of the machine by its operator.

In order to support the part G of the shaft carrying arm in any desiredpositioma sleeve, h, is secured thereon, which sleeve extends downbeneath the arm far enough to allow the toothed rack k to slide thereinbeneath the arm. One end of this rack is pivoted to a connecting-rod, l,the opposite endot' which is carried by the lug m, projecting from thebracket F. This rod acts as a brace to support the arms, the position ofwhich is adjusted by means of a spring-dog, i, pivoted upon the underside of the sleeve it, its toe passing through an oritice in the same,so as to engage with the tooth of the rack k, and thus hold the arms atany desired elevation.

The method of operation of machines of this class is well known, anddoes not therefore need tobe described in detail, the novel points inthis enginebeing the addition of the handle to the standard forconvenience in changing its position, the construction and arrangementof the spring by which the extension-bar is supported, the devices foradjustably holding up the shaft-carrying arm, and the globular universaljoint in the same, by means of which the operator is given a bettercontrol over the machine and the instrument in use.

Having thus described our invention, we claim as new, and desire tosecure by Letters Patent, the following:

l. [n a dental engine, the combination of thebase A, abit'urcated androtating standard, B, the extensionbar D, with bifurcated arms extendingat an angle from and pivoted to the bifurcations of said standard, andthe handle a, connecting the two parts of the standards above itsattachment to the extension-bar,substantially as shown and described.

2. In a dental engine, the combination,with the standard and extensionbar having a bifurcated connection with said standard at right angles tothe body of the bar, of the double spring I), attached to the bar andadjustable upon the standard, as specified.

3. In a dental engine, the combination of the extension bar D with theshaftcarrying case G, the sleeve 7:, placed upon said case, thespring-dog i, attached to the sleeve, the rack Ir, sliding through thesleeve and engaging with the spriug-dog,a11d the connectingrod pivotedat one end to the rack and at the other to the extension be r to form anadjustable brace for retaining the shaftcase Gin any desired positionwith relation to the extensioirbar, as specified.

in a dental engine, the combination of the shaft-cases G and G with thecups I and 1, attached by sleeves to said cases and connected togetherby flanges, forming a universal joint, the parts l ilngj adapted to turnone upon the other, substantially as shown and described.

5. in a dental engine, the shat'tcases G and G, united by a globularuniversal joint, in combination with the shaft inclosed in said eases,consisting of two rigid parts, II and H, within the cases, and theflexible wire coil J, connecting the rigid parts within the globularjoint, substantially as shown and described.

I n testimony whereof we affix our signatures in presence of twowitnesses.

JOHN HOOD. I S'lElllET\ ll'. REYNOLDS.

\Vitnesses:

.lonN )IAY, Wu. H. COMIC.

